invention relates to novel medicinal compositions having substantial diuretic and/or antihypertensive activities. The invention relates to two solutions, one of triamterene and the other, a solution of triamterene and hydrochlorothiazide.
Triamterene is 2,4,7-triamino-6-phenylpteridine. Hydrochlorothiazide is 6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. Triamterene is a diuretic and the combination of triamterene and hydrochlorothiazide is a diuretic with antihypertensive properties. As is known, the hydrochlorothiazide component blocks the reabsorption of sodium and chloride ions thereby increasing the quantity of sodium traversing the distal tubule and the volume of water excreted. Although the exact antihypertensive effect of hydrochlorothiazide is not known, the continued use of the drug decreases the excretion of uric acid and may increase the excretion of iodide and may also reduce glomerular filtration rate. The triamterene exerts its diuretic effect as does hydrochlorothiazide except that it only inhibits the reabsorption of sodium in exchange for potassium and hydrogen ions.
Both of the drugs exhibit approximately the same duration of effectiveness in that they both have peak activity at two to three hours after ingestion with tapering effectiveness during the subsequent seven to nine hours. The combination of both triamterene and hydrochlorothiazide finds particular usefulness in the treatment of edema and has been indicated as injunctive therapy associated with congestive heart failure, hepatic cirrhosis and the nephrotic syndrome. General dosage has been set at 100 mg triamterene and 100-200 mg triamterene and 50-100 mg hydrochlorothiazide in divided doses. The drug is available in solid form administered as capsules.
It has now been discovered that a liquid form of triamterene and/or a liquid form of triamterene and hydrochlorothiazide may be delivered. It is important to provide an oral solution because it is easier to administer and for some easier to ingest. Heretofore, a solution has not been available because triamterene is extremely insoluble and has not been able to be put into a stable solution capable of being ingested as a pharmaceutical preparation.
Accordingly, it is an object of the present invention to provide a pharmaceutically acceptable solution of triamterene.
It is another object of the present invention to provide a pharmaceutically acceptable solution of triamterene and hydrochlorothiazide capable of being administered orally.
The invention contemplates the solubilization of triamterene in a combination of glycols and lactic acid. It has been found that either the presence of lactic acid or an acid salt thereof alone is insufficient to cause triamterene to be solubilized, and it has been found that the combination of triamterene and glycol or combinations of propylene glycol and polyethylene glycol is insufficient to cause the triamterene to go into solution. However, it has been found that a combination of glycol and lactic acid or an acid salt thereof when combined with triamterene causes the triamterene to become soluble. This solubilization of triamterene remains effective even when mixed with hydrochlorothiazide.
In a commercial solution, various preservatives such as methylparaben and sodium benzoate or propylparaben or benzoic acid or other known preservatives which are pharmaceutically acceptable or various combinations thereof may be used as required and is well known. In addition, a wide variety of colors and flavors as well as various combinations of flavors and colors may also be used in a commercial preparation. For instance, sodium saccharin may be used as a sweetening agent and various colors all of which must be pharmaceutically acceptable may be used in the product. The presence of various preservatives, sweetening agents, flavors and colors do not form any part of the invention but may be included in a commercial preparation.
A diluent or carrier is provided in the commercial embodiment. The diluent or carrier which is preferred is glycerin, but other well known diluents that are pharmaceutically acceptable carriers may be substituted for glycerin without affecting the efficacy of the invention. Generally, glycerin or other pharmaceutically acceptable carrier or diluent should be present in the range of from about 0.5% by volume to about 55% by volume. The preferred concentration of diluent or carrier is in the range of from about 20% by volume to about 50% by volume. It is also contemplated that buffers may be required; however, at present it appears that buffers are not required. The optimum pH range for the solution is from about 4.0 to 6.0. If buffers are required for a commercial solution, it is within the scope of the invention.
As a required element of the invention, glycols must be present. While a large variety of glycols may be useful, propylene glycol and/or polyethylene glycol are preferred. Generally, glycols having a molecular weight from about 200 to about 6000 are preferred and are selected from various combinations of propylene glycol or polyethylene glycol. Glycol should be present in the solution in a concentration in the range of from about 1% by volume to about 50% by volume. While propylene glycol may be used alone, it may be used in combination with as much as 50% polyethylene glycol. A requirement for the solubilization of triamterene is the presence of both glycol and lactic acid or a acid salt thereof. It has been found that with the amount of glycol required as stated above, lactic acid should be present in the amount of 2% for each 1% triamterene, and it has been found that the amount of lactic acid must be proportionally increased if the concentration of triamterene is increased or the amount of lactic acid may be proportionally decreased if the concentration of triamterene is decreased. For instance, if triamterene having a concentration of 5 mg/ml is used, then the amount of lactic acid required is 1%. Generally, lactic acid may be present in the range of from about 0.5% to about 20%.
Various commercial formulas have been prepared and the procedure has been as follows. An amount of polyethylene glycol-600 and propylene glycol has been added to a main tank and agitated. Thereafter the triamterene is added to the glycol and agitated but none of the triamterene is dissolved. Thereafter the lactic acid in the above specified amount is added with continued agitation which causes the triamterene to dissolve.
In a separate container the hydrochlorothiazide and methylparaben is dissolved in propylene glycol and a polyethylene glycol combination which is warmed to about 50.degree. C. Then the combination of glycol, hydrochlorothiazide and methylparaben is added to the main tank containing the dissolved triamterene. Thereafter in a separate container the sodium benzoate is warmed in purified water to a temperature of between 40.degree. and 45.degree. C. and added to the main tank which is continually agitated.
Thereafter, the sodium saccharin is added to a warmed (45.degree.--45.degree. C.) quantity of glycerin and then both are added to the main tank which has been continually agitated. Finally, the remainder of the glycerin is added. Various flavors may be added such as chocolate extract or other additives such as raspberry oil and anise oil dissolved in or mixed with propylene glycol. At this point the coloring solution may be added such as FD&C Red #40 in purified water and may be filtered and added to the main tank which is under continual agitation. Then, the total batch volume may be diluted with glycerin, and mixed for no less than about thirty minutes, if the batch volume is 900 gallons or less. If the batch volume is over 900 gallons, mixing should be continuous for about sixty minutes.